CN110988760B - Digital signal detection system of Mx cesium light pump magnetometer - Google Patents
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- 238000001514 detection method Methods 0.000 title claims abstract description 25
- TVFDJXOCXUVLDH-UHFFFAOYSA-N caesium atom Chemical compound [Cs] TVFDJXOCXUVLDH-UHFFFAOYSA-N 0.000 title claims abstract description 21
- 229910052792 caesium Inorganic materials 0.000 title claims abstract description 20
- 230000003287 optical effect Effects 0.000 claims abstract description 25
- 230000001419 dependent effect Effects 0.000 claims abstract description 13
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- 241001565477 Aphyosemion omega Species 0.000 claims description 2
- 238000005259 measurement Methods 0.000 abstract description 12
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- 238000010586 diagram Methods 0.000 description 4
- 238000010521 absorption reaction Methods 0.000 description 3
- 229910052734 helium Inorganic materials 0.000 description 3
- 239000001307 helium Substances 0.000 description 3
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 3
- 230000010363 phase shift Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 230000003595 spectral effect Effects 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
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- 239000000284 extract Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 229910052701 rubidium Inorganic materials 0.000 description 1
- IGLNJRXAVVLDKE-UHFFFAOYSA-N rubidium atom Chemical compound [Rb] IGLNJRXAVVLDKE-UHFFFAOYSA-N 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/24—Arrangements or instruments for measuring magnetic variables involving magnetic resonance for measuring direction or magnitude of magnetic fields or magnetic flux
- G01R33/26—Arrangements or instruments for measuring magnetic variables involving magnetic resonance for measuring direction or magnitude of magnetic fields or magnetic flux using optical pumping
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Abstract
A digital signal detection system of Mx cesium optical pump magnetometer, the digital driving signal produced by the numerical control oscillator, after converting into analog signal through the digital-to-analog converter, drive the magneto-dependent sensor, the numerical control oscillator outputs the signal to the digital lock-in amplifier; the analog-to-digital converter converts the received electric signal into a digital signal, outputs amplitude and phase signals after passing through the digital phase-locked amplifier, and uploads the digital signal to a computer through the serial port module and the serial port communication line, and the phase signals also serve as control signals to enter the digital controller; the digital controller selects a detection mode according to the control of the computer to control the output signal frequency of the numerical control oscillator, and the output signal frequency is uploaded to the computer; the digital control oscillator also receives a phase control word output by the computer, the digital lock-in amplifier, and clock signals of the digital control oscillator, the digital controller and the serial port module are divided by an external active crystal oscillator through a frequency divider to obtain various required clocks. The invention has the advantages of rich functions, low debugging difficulty, high measurement precision and high integration level.
Description
Technical Field
The invention relates to a digital signal detection system of an optical pump magnetometer. In particular to a digital signal detection system of an Mx cesium optical pump magnetometer.
Background
The optical pump magnetometer is a magnetic field measuring instrument based on the Zeeman effect of working atoms in a magnetic field and manufactured by utilizing the technology of combining optical pumping and magnetic resonance, and has the advantages of high sensitivity, high precision, quick response, no zero drift and the like. The optical pump magnetometer is divided into a helium optical pump magnetometer and an alkali metal (comprising potassium, rubidium and cesium) optical pump magnetometer according to working substances; the structure of the magnetic sensing probe is divided into Mz type and Mx type. The helium optical pump magnetometer is usually manufactured into a tracking magnetic measurement system by adopting an Mz structure, and the magnetic field value is calculated according to the linear relation between the frequency and the measured magnetic field by measuring the frequency of a radio frequency signal when the light intensity of light transmitted through the helium absorption chamber is weakest, namely when optical magnetic resonance occurs. The cesium optical pump magnetometer generally adopts an Mx type, an included angle is formed between the direction of a light beam in a magneto-sensitive sensing probe and the direction of an external magnetic field, a radio frequency magnetic field parallel to the direction of the light beam modulates the absorption coefficient of cesium atoms to light by the frequency of a radio frequency signal, the light signal transmitted through the cesium absorption air chamber contains an alternating component with the same frequency as the radio frequency signal, a phase shift exists between the light signal and the radio frequency signal, the range is 0-180 degrees, when the frequency of the radio frequency signal is equal to the resonance frequency, the system generates an optical magnetic resonance effect, the phase shift of the light signal relative to the radio frequency signal is 90 degrees, and the magnetic field value to be measured can be obtained by measuring the frequency of the radio frequency signal.
The simplest magnetic measurement method of the Mx-type cesium optical pump magnetometer is self-oscillation type, the detection method is realized by a phase-shifting amplifying circuit and a frequency measurement circuit, the circuit structure is simple, the response is quick, but the temperature drift is large, the anti-interference capability is weak, the frequency measurement circuit can introduce frequency measurement errors, and the resonance signal spectral line cannot be detected. Another magnetic measurement method of the Mx cesium optical pump magnetometer is a phase-locked mode, and it is common that a phase-locked amplifier formed by a phase-sensitive detector and an integrating circuit extracts phase information of a resonance signal, and the phase controls a radio frequency driving signal and a reference signal frequency output by a voltage-controlled oscillator through a feedback control loop. In addition, the amplitude and the phase of the resonance signal can be accurately measured by adopting a mature product of a commercially available phase-locked amplifier, but the cost is high, the size is large, and the integration and the miniaturization of the magnetometer are not facilitated.
Disclosure of Invention
The invention aims to solve the technical problem of providing a digital signal detection system of an Mx cesium optical pump magnetometer, which integrates a signal detection system on a single FPGA chip based on a programmable gate array (FPGA), and has the advantages of rich functions, low debugging difficulty, high measurement precision and high integration level.
The technical scheme adopted by the invention is as follows: the digital signal detection system of the Mx-type cesium optical pump magnetometer comprises a magneto-dependent sensor, and is further provided with an analog-to-digital converter, a digital-to-analog converter, an FPGA chip, an active crystal oscillator and a computer, wherein the FPGA chip comprises a digital phase-locked amplifier, a numerical control oscillator, a digital controller, a serial port module and a frequency divider, wherein the numerical control oscillator generates a digital driving signal, the digital driving signal is converted into an analog signal through the digital-to-analog converter and then drives a radio-frequency coil in the magneto-dependent sensor to generate a radio-frequency magnetic field, and meanwhile, the numerical control oscillator outputs a quadrature reference signal to be provided for the digital phase-locked amplifier; the analog-to-digital converter converts the voltage signal to be detected output by the magneto-dependent sensor into a digital signal to be detected and outputs the digital signal to the digital lock-in amplifier; the digital phase-locked amplifier performs phase-sensitive detection calculation on a digital signal to be detected, outputs amplitude and phase signals, uploads the amplitude and phase signals to a computer through a serial port module and a serial port communication line, and the phase signals output by the digital phase-locked amplifier are used as control signals to enter a digital controller; the digital controller selects a detection mode according to a mode control signal sent by the computer, a frequency control word output by the digital controller controls the output signal frequency of the numerical control oscillator, and the frequency control word output by the digital controller is also uploaded to the computer through the serial port module; the digital control oscillator also receives a phase control word output by the computer, the digital lock-in amplifier in the FPGA chip, and clock signals of the digital control oscillator, the digital controller and the serial port module are divided by an external active crystal oscillator through a frequency divider to obtain various required clocks.
The digital signal detection system of the Mx-type cesium optical pump magnetometer has the advantages of rich functions, low debugging difficulty, high measurement precision and high integration level. The invention has the following advantages:
(1) The invention has rich functions and high automation degree, can switch between an open loop mode and a closed loop mode, and detects the resonance signal spectral line in the open loop mode for the system debugging of the magnetometer, and the closed loop mode is used for real-time measurement.
(2) The invention does not need a high-precision frequency measuring circuit, the frequency of the driving signal is directly obtained by the frequency control word, and the frequency measuring error is eliminated.
(3) The FPGA chip adopted by the invention is parallel, the operation is rapid and stable, the design and development are in a software programming mode, and compared with an analog hardware circuit, the debugging difficulty is lower.
(4) The invention adopts a full-digital signal detection system, integrates the lock-in amplifier, the signal generator, the feedback controller and the serial port on one FPGA chip, has strong anti-interference capability, high integration degree, small volume and low cost, and is beneficial to expanding the application field of cesium optical pump magnetometers.
Drawings
FIG. 1 is a block diagram of a digitized signal detection system of an Mx-type cesium optical pump magnetometer of the present invention;
FIG. 2 is a block diagram of the configuration of a digitally controlled oscillator of the present invention;
FIG. 3 is a block diagram of the digital lock-in amplifier of the present invention;
fig. 4 is a block diagram of the digital controller according to the present invention.
In the figure
1: Magneto-dependent sensor 2: analog-to-digital converter
3: Digital-to-analog converter 4: FPGA chip
5: Digital lock-in amplifier 5.1: first multiplier
5.2: Second multiplier 5.3: first low-pass filter
5.4: Second low pass filter 5.5: CORDIC module
6: Numerical control oscillator 6.1: phase accumulator
6.11: First phase register 6.12: second phase register
6.2: Waveform memory 6.21: first sine lookup table
6.22: Cosine lookup table 6.23: second sine lookup table
7: A digital controller 7.1; sweep frequency controller
7.2: Digital PID controller 7.3: mode controller
8: Serial port module 9: frequency divider
10: Active crystal oscillator 11: serial port communication line
12: Computer with a memory for storing data
Detailed Description
The following describes a digital signal detection system of an Mx cesium optical pump magnetometer according to the present invention in detail with reference to the examples and the accompanying drawings.
As shown in fig. 1, the digital signal detection system of the Mx cesium optical pump magnetometer comprises a magneto-dependent sensor 1, an analog-to-digital converter 2, a digital-to-analog converter 3, an FPGA chip 4, an active crystal oscillator 10 and a computer 12, wherein the FPGA chip 4 comprises a digital lock-in amplifier 5, a digital controlled oscillator 6, a digital controller 7, a serial port module 8 and a frequency divider 9, wherein the digital controlled oscillator 6 generates a digital driving signal, converts the digital driving signal into an analog signal through the digital-to-analog converter 3 and drives a radio-frequency coil in the magneto-dependent sensor 1 to generate a radio-frequency magnetic field, and meanwhile, the digital controlled oscillator 6 outputs a quadrature reference signal to be provided for the digital lock-in amplifier 5; the analog-to-digital converter 2 converts the voltage signal to be detected output by the magneto-dependent sensor 1 into a digital signal to be detected, and outputs the digital signal to the digital lock-in amplifier 5 to serve as the signal to be detected of the digital lock-in amplifier 5; the digital phase-locked amplifier 5 carries out phase-sensitive detection calculation on the digital signal to be detected, outputs amplitude and phase signals, and uploads the amplitude and phase signals to the computer 12 through the serial port module 8 and the serial port communication line 11, and the phase signals output by the digital phase-locked amplifier 5 are used as control signals to enter the digital controller 7; the digital controller 7 selects a detection mode according to a mode control signal sent by the computer 12, the frequency control word is controlled to be output by the sweep frequency controller in an open loop mode, the frequency control word is controlled to be output according to the phase control output by the digital phase-locked amplifier 5 in a closed loop mode, the frequency control word output by the digital controller 7 controls the output signal frequency of the numerical control oscillator 6, and the frequency control word output by the digital controller 7 is also uploaded to the computer 12 through the serial port module 8; the digital control oscillator 6 also receives a phase control word output by the computer 12, the digital lock-in amplifier 5 in the FPGA chip 4, and clock signals of the digital control oscillator 6, the digital controller 7 and the serial port module 8 are divided by an external active crystal oscillator 10 through a frequency divider 9 to obtain various required clocks.
As shown in fig. 2, the digitally controlled oscillator 6 generates a driving signal and a quadrature reference signal using a direct digital frequency synthesis (DDS) technique. The numerical control oscillator 6 comprises: and a phase accumulator 6.1 for accumulating the reference signal phase control word Pr and the driving signal phase control word Pd provided by the computer 12 and the frequency control word K provided by the digital controller 7, and a waveform memory 6.2 for respectively receiving the address signals output by the phase accumulator 6.1, wherein the waveform memory 6.2 respectively outputs the reference signals to the digital phase-locked amplifier 5 and outputs the driving signals to the digital-to-analog converter 3, and the phase accumulator 6.1 and the waveform memory 6.2 also receive the system clock signals.
The phase control word Pr sets the compensation phase of the reference signal and counteracts the phase shift of the driving signal by electronic devices except the magneto-dependent sensor 1 in the magnetometer detection system; the phase control word Pd sets the drive signal phase, typically to 0.
The frequency f 0 expression of the reference signal and the driving signal output by the numerically controlled oscillator 6 is as follows:
the minimum output frequency when k=1, i.e., the frequency resolution Δf is:
wherein: f c is the system clock frequency, K is the frequency control word, and N is the number of bits of the phase accumulator.
The phase accumulator 6.1 comprises a first phase register 6.11 and a second phase register 6.12, wherein the output of the first phase register 6.11 is added with a frequency control word K and then is input into the first phase register 6.11, the output of the first phase register 6.11 is added with a phase control word Pr and then is output into the waveform memory 6.2, the output of the second phase register 6.12 is added with the frequency control word K and then is input into the second phase register 6.12, and the output of the second phase register 6.12 is added with a phase control word Pd and then is output into the waveform memory 6.2.
The waveform memory 6.2 includes a first sine lookup table 6.21, a cosine lookup table 6.22 and a second sine lookup table 6.23, wherein the first sine lookup table 6.21 and the cosine lookup table 6.22 receive the first address signal and output 2 reference signals to the digital lock-in amplifier 5, and the second sine lookup table 6.23 receives the second address signal and outputs a driving signal to the digital-to-analog converter 3.
As shown in fig. 3, the digital lock-in amplifier 5 includes a first multiplier 5.1, a second multiplier 5.2, a first low-pass filter 5.3, a second low-pass filter 5.4 and a CORDIC module 5.5, wherein the first multiplier 5.1 multiplies a received digital signal to be detected by a reference signal output by the numerically controlled oscillator 6, and then sends the digital signal to be detected to the first low-pass filter 5.3 for low-pass filtering, the second multiplier 5.2 multiplies the received digital signal to be detected by another reference signal output by the numerically controlled oscillator 6, and then sends the digital signal to the second low-pass filter 5.4 for low-pass filtering, the outputs of the first low-pass filter 5.3 and the second low-pass filter 5.4 are jointly sent to the CORDIC module 5.5, the amplitude signal and the phase signal are respectively output by the CORDIC module 5.5 and are uploaded to the computer 12 through the serial port module 8 and the serial port communication line 11, and the output phase signal is also sent to the digital controller 7.
The digital phase-locked amplifier 5 adopts an orthogonal phase-sensitive detection algorithm, and the expression is as follows
Wherein: A. omega,Respectively the amplitude, angular frequency and phase of the signal to be measured, n (t) being noise;
the reference signal is a pair of orthogonal sine signal and cosine signal generated by a numerical control oscillator (6), and the expression is
Wherein: a r, ω,Reference signal amplitude, angular frequency and phase, respectively;
Multiplying the signal to be detected and the orthogonal reference signal by a multiplier, namely multiplying the equation (3) with the equations (4) and (5) respectively to obtain a mixed signal
The two mixed signals are respectively filtered by a first low-pass filter (5.3) and a second low-pass filter (5.4) to remove the frequency doubling component and noise, and only the direct current component is remained, namely the in-phase component I and the quadrature component Q of the signal to be detected are output, namely
Inputting the in-phase component I and the quadrature component Q into a CORDIC module, and calculating the amplitude A and the phase difference of the signal to be detected through a vector mode of a CORDIC algorithmI.e.
As shown in fig. 4, the digital controller 7 includes a sweep frequency controller 7.1, a digital PID controller 7.2 and a mode controller 7.3, wherein the sweep frequency controller 7.1 generates a frequency control word and outputs the frequency control word to an a mode of the mode controller 7.3, the digital PID controller 7.2 inputs a phase difference between a signal to be measured and a reference signal, outputs the frequency control word to a B mode of the mode controller 7.3, and the mode controller 7.3 selects the frequency control word of the a mode or the B mode according to a mode control signal input by the computer 12 through the serial port module 8.
The A mode is open loop control, a frequency control word is generated by the sweep frequency controller 7.1, the frequency control word is stepped once at intervals of a certain time, the numerical control oscillator 7 is controlled to output signals in a certain frequency range, and the resonance line type of the amplitude and the phase of the signals to be detected is detected. The B mode is closed loop control, the input is the phase difference between the signal to be detected and the reference signal, the output is a frequency control word, the phase difference is locked at 90 degrees by adopting a PID control algorithm, and the magnetic measurement system is at a resonance point.
The FPGA chip 4 and the computer 12 communicate through the serial port module 8 and the serial port communication line 11, and adopt an RS232 protocol. The computer 12 receives the amplitude and the phase of the signal to be detected calculated in the FPGA chip 4 and the frequency control word output by the digital controller 7; the FPGA chip 4 receives the mode control signal and the phase control word transmitted by the computer 12. When the system is at the resonance point, the software on the computer 12 directly calculates the magnetic field value by the frequency control word according to the magnetic measurement formula, wherein the magnetic measurement formula is f= 3.49828B (12)
Wherein: the unit of f is Hz and the unit of B is nT.
The specific implementation steps are as follows:
1. the magneto-dependent sensor 1 is placed in an external magnetic field to be measured, and an included angle is formed between the axis and the direction of the external magnetic field, and the angle is optimal at 45 degrees;
2. initializing the FPGA chip 4, including initializing a serial port module and related registers;
3. opening the computer 12, and testing the communication condition of the computer 12 and the FPGA chip 4;
5. Setting the phases and detection modes of the drive signal and the reference signal on the computer 12, and clicking to start detection;
6. In the sweep frequency mode, waiting for the display interface to draw a resonance signal spectrum line, and storing the signal spectrum line for subsequent data processing and system debugging;
7. And in a real-time measurement mode, observing and displaying a magnetic field value curve of the interface, and obtaining the external magnetic field value to be measured after the magnetic field value is kept stable.
Claims (4)
1. The digital signal detection system of the Mx-type cesium optical pump magnetometer comprises a magneto-dependent sensor (1) and is characterized by further comprising an analog-to-digital converter (2), a digital-to-analog converter (3), an FPGA chip (4), an active crystal oscillator (10) and a computer (12), wherein the FPGA chip (4) comprises a digital lock-in amplifier (5), a numerical control oscillator (6), a digital controller (7), a serial port module (8) and a frequency divider (9), wherein the numerical control oscillator (6) generates a digital driving signal, the digital driving signal is converted into an analog signal through the digital-to-analog converter (3) and then drives a radio-frequency coil in the magneto-dependent sensor (1) to generate a radio-frequency magnetic field, and the numerical control oscillator (6) outputs a quadrature reference signal to be provided for the digital lock-in amplifier (5); the analog-to-digital converter (2) converts a voltage signal to be detected output by the magneto-dependent sensor (1) into a digital signal to be detected and outputs the digital signal to the digital lock-in amplifier (5); the digital phase-locked amplifier (5) carries out phase-sensitive detection calculation on a digital signal to be detected, outputs amplitude and phase signals, and uploads the amplitude and phase signals to the computer (12) through the serial port module (8) and the serial port communication line (11), and the phase signals output by the digital phase-locked amplifier (5) are used as control signals to enter the digital controller (7); the digital controller (7) selects a detection mode according to a mode control signal sent by the computer (12), a frequency control word output by the digital controller (7) controls the output signal frequency of the numerical control oscillator (6), and the frequency control word output by the digital controller (7) is also uploaded to the computer (12) through the serial port module (8); the digital control oscillator (6) also receives a phase control word output by the computer (12), the digital lock-in amplifier (5) in the FPGA chip (4), and clock signals of the digital control oscillator (6), the digital controller (7) and the serial port module (8) are divided by an external active crystal oscillator (10) through a frequency divider (9) to obtain various required clocks;
The numerical control oscillator (6) comprises: a phase accumulator (6.1) for accumulating the reference signal phase control word Pr and the driving signal phase control word Pd provided by the computer (12) and the frequency control word K provided by the digital controller (7) respectively, a waveform memory (6.2) for receiving the address signals output by the phase accumulator (6.1) respectively, wherein the waveform memory (6.2) outputs the reference signals to the digital phase-locked amplifier (5) respectively, outputs the driving signals to the digital-to-analog converter (3), and the phase accumulator (6.1) and the waveform memory (6.2) also receive the system clock signals;
The phase accumulator (6.1) comprises a first phase register (6.11) and a second phase register (6.12), wherein the output of the first phase register (6.11) is added with a frequency control word K and then is input into the first phase register (6.11), the output of the first phase register (6.11) is added with a phase control word Pr and then is output into the waveform memory (6.2), the output of the second phase register (6.12) is added with the frequency control word K and then is input into the second phase register (6.12), and the output of the second phase register (6.12) is added with a phase control word Pd and then is output into the waveform memory (6.2);
The waveform memory (6.2) comprises a first sine lookup table (6.21), a cosine lookup table (6.22) and a second sine lookup table (6.23), wherein the first sine lookup table (6.21) and the cosine lookup table (6.22) receive a first address signal and output 2 reference signals to the digital lock-in amplifier (5), and the second sine lookup table (6.23) receives a second address signal and outputs a driving signal to the digital-to-analog converter (3);
The digital controller (7) comprises a sweep frequency controller (7.1), a digital PID controller (7.2) and a mode controller (7.3), wherein the sweep frequency controller (7.1) generates a frequency control word and outputs the frequency control word to an A mode of the mode controller (7.3), the digital PID controller (7.2) inputs a phase difference between a signal to be detected and a reference signal, the frequency control word is output to a B mode of the mode controller (7.3), and the mode controller (7.3) selects the frequency control word of the A mode or the B mode according to a mode control signal input by the computer (12) through the serial port module (8).
2. The digitized signal detection system of the Mx type cesium optical pump magnetometer according to claim 1, characterized in that the frequency f 0 expression of the reference signal and the driving signal output by the numerically controlled oscillator (6) is:
the minimum output frequency when k=1, i.e., the frequency resolution Δf is:
wherein: f c is the system clock frequency, K is the frequency control word, and N is the number of bits of the phase accumulator.
3. The digitized signal detection system of the Mx type cesium optical pump magnetometer according to claim 1, characterized in that the digital lock-in amplifier (5) includes a first multiplier (5.1), a second multiplier (5.2), a first low-pass filter (5.3), a second low-pass filter (5.4) and a CORDIC module (5.5), where the first multiplier (5.1) multiplies a received digital signal to be detected by a reference signal output by the numerically controlled oscillator (6) and then sends the digital signal to be detected to the first low-pass filter (5.3) for low-pass filtering, the second multiplier (5.2) multiplies the received digital signal to be detected by another reference signal output by the numerically controlled oscillator (6) and then sends the digital signal to the second low-pass filter (5.4) for low-pass filtering, and the outputs of the first low-pass filter (5.3) and the second low-pass filter (5.4) are jointly sent to the CORDIC module (5.5), and the digital signal to be detected is sent to the phase string module (8) through the phase string of the phase detector (7) and the phase detector (11) for calculating the amplitude.
4. The digitized signal detection system of said Mx-type cesium optical pump magnetometer of claim 3, wherein said digital lock-in amplifier (5) employs an orthogonal phase-sensitive detection algorithm expressed as
Wherein: A. omega,Respectively the amplitude, angular frequency and phase of the signal to be measured, n (t) being noise;
the reference signal is a pair of orthogonal sine signal and cosine signal generated by a numerical control oscillator (6), and the expression is
Wherein: a r, ω,Reference signal amplitude, angular frequency and phase, respectively;
Multiplying the signal to be detected with the orthogonal reference signal multiplier, namely multiplying the equation (3) with the equations (4) and (5) respectively to obtain a mixed signal
The two mixed signals are respectively filtered by a first low-pass filter (5.3) and a second low-pass filter (5.4) to remove the frequency doubling component and noise, and only the direct current component is remained, namely the in-phase component I and the quadrature component Q of the signal to be detected are output, namely
Inputting the in-phase component I and the quadrature component Q into a CORDIC module, and calculating the amplitude A and the phase difference of the signal to be detected through a vector mode of a CORDIC algorithmI.e.
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Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5467294A (en) * | 1994-03-09 | 1995-11-14 | Hu; Vince | High speed, low power direct digital synthesizer |
| CN101276002A (en) * | 2007-03-26 | 2008-10-01 | 中国海洋石油总公司 | High temperature monolithic phase programmable direct numerical frequency synthetic source |
| CN102201819A (en) * | 2011-03-07 | 2011-09-28 | 武汉理工大学 | Frequency synthesis source applied by DDS short-wave transmitter based on CPLD design |
| CN202929184U (en) * | 2012-12-11 | 2013-05-08 | 吉林大学 | Helium optical pump magnetic resonance signal fully digital detection device |
| CN103957007A (en) * | 2014-05-09 | 2014-07-30 | 武汉工程大学 | Random waveform weak signal detection method and system under low signal to noise ratio |
| CN104483554A (en) * | 2014-12-31 | 2015-04-01 | 思澜科技（成都）有限公司 | Digital phase demodulating method and system for bioelectricity impedance measurement |
| CN107134996A (en) * | 2017-04-27 | 2017-09-05 | 中山大学 | A kind of digital lock-in amplifier of many reference models |
| CN109714046A (en) * | 2019-03-05 | 2019-05-03 | 南华大学 | The all-digital phase-locked loop and locking phase control method of variable phase accumulator circuit structure |
| CN208888686U (en) * | 2018-11-23 | 2019-05-21 | 天津光电通信技术有限公司 | A kind of radio-frequency front-end Direct Digital Frequency Synthesizers |
| CN212134928U (en) * | 2019-12-06 | 2020-12-11 | 天津大学 | Digital signal detection system of Mx type cesium optical pump magnetometer |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB0121713D0 (en) * | 2001-09-07 | 2001-10-31 | Nokia Corp | Accumulator based phase locked loop |
-
2019
- 2019-12-06 CN CN201911245312.8A patent/CN110988760B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5467294A (en) * | 1994-03-09 | 1995-11-14 | Hu; Vince | High speed, low power direct digital synthesizer |
| CN101276002A (en) * | 2007-03-26 | 2008-10-01 | 中国海洋石油总公司 | High temperature monolithic phase programmable direct numerical frequency synthetic source |
| CN102201819A (en) * | 2011-03-07 | 2011-09-28 | 武汉理工大学 | Frequency synthesis source applied by DDS short-wave transmitter based on CPLD design |
| CN202929184U (en) * | 2012-12-11 | 2013-05-08 | 吉林大学 | Helium optical pump magnetic resonance signal fully digital detection device |
| CN103957007A (en) * | 2014-05-09 | 2014-07-30 | 武汉工程大学 | Random waveform weak signal detection method and system under low signal to noise ratio |
| CN104483554A (en) * | 2014-12-31 | 2015-04-01 | 思澜科技（成都）有限公司 | Digital phase demodulating method and system for bioelectricity impedance measurement |
| CN107134996A (en) * | 2017-04-27 | 2017-09-05 | 中山大学 | A kind of digital lock-in amplifier of many reference models |
| CN208888686U (en) * | 2018-11-23 | 2019-05-21 | 天津光电通信技术有限公司 | A kind of radio-frequency front-end Direct Digital Frequency Synthesizers |
| CN109714046A (en) * | 2019-03-05 | 2019-05-03 | 南华大学 | The all-digital phase-locked loop and locking phase control method of variable phase accumulator circuit structure |
| CN212134928U (en) * | 2019-12-06 | 2020-12-11 | 天津大学 | Digital signal detection system of Mx type cesium optical pump magnetometer |
Non-Patent Citations (1)
| Title |
|---|
| 光泵磁敏传感器中FPGA调频器设计与实现;连明昌;程德福;周志坚;王君;何聪;;传感技术学报;20121115(11);全文 * |
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